Peritonitis

History

Fact

Explanation

Usually occurs due to an infection

This is a common emergency. peritoneum is the serosal memebrane which lines the abdominal cavity. When this serosal membrane gets inflamed, it's known as Peritonitis. It is either infectious or sterile or either primary or secondary. Infective microorganisms can cause infectious peritonitis. Perforation of a viscus which releases blood, bile acid, feces is another method in which peritonitis occurs. There's usually no underlying pathology for primary or spontaneous peritonitis but secondary is due to an underlying secondary cause. [1] [2] [3]

Fever with chills [5]

Underlying sepsis is the cause. Micro-organisms, white blood cells release interleukins which act on the thermo regulatory centre in the hypothalamus anc causes high temperature. [5]

Abdominal pain or discomfort [3] [4]

Pain is diffuse when visceral peritoneum is inflamed but rather sharp and localized when it involves the parietal peritoneum. Diagnosis of peritonitis is usually clinical. Patient usually lies still as the movement exacerbates the pain. In the history previous abdominal surgery, previous history of peritonitis, Immunosuppressive agents, and history of pepitc ulcer disease, diverticlulits, inflammatory bowel disease need to be inquired. [3] [4]

Anorexia, nausea, vomiting [6]

Intestinal obstruction due to underlying pathology Ex: obstruction of the proximal intestine can cause nausea and vomiting. [6]

Diarrhea [6]

Due to underlying ileus/ paralysis of intestines. The intestinal paralysis that follows peritonitis is explained as the result of local inflammation of the overlying serosa (Stokes's law). When peritonitis was achieved, all motor activity ceased in the intracavitary loops. [6]

Ascites [7]

This is due to transudation of fluid through serosal membranes when these are inflamed. [7]

Inability to pass urine, confusion [7]

These symptoms usually indicate the presence of acute renal failure. Because of fluid transduation and causes hypovolemia. This leads to inadequate perfusion of the kidney and acute renal failure. [7]

Examination

Fact

Explanation

Fever/ Hypothermia [1] [6]

Most of the patients are febrile and Elevated temperature is due to release of inflammatory mediators from micro-organisms which act on the thermo-regulatory centre in the hypothalamus. Septicemia can sometimes present with hypothermia [1] [6]

Toxic/ ill looking [1] [5]

Patient maybe severely septic and appear ill looking. [1] [5]

Tachycardia [1] [2] [5]

Tachycardia is also due to release of inflammatory mediators [1] [2] [5]

Abdominal wall rigidity is a phenomenon that is observed during abdominal examination in which is the patient voluntarily increases the muscle tone when anticipating palpation of the abdomen due to pain. Guarding is involuntary increase in the tone. [1] [5]

Tenderness on abdominal palpation [1] [5]

Tenderness to palpation is common usually indicates the underlying pathology. [1] [5]

Distension of the abdomen/ Abdominal mass [1] [5]

The abdomen is often distended due to ascitis. Occasionally a mass can be present such as inflammatory mass like inflamed appendix. [1] [5]

Absent bowel sounds [1] [5]

Stokes's law implies the intestinal paralysis which follows peritonitis as a result of local inflammation of the overlying serosa. Therefore all motor activity ceased in the intracavitary loops and ileus results, bowel sounds maybe absent. [1] [5]

pain during digital rectal examination (DRE) [1] [4] [5]

Inflamed pelvic appendix may cause pain only during a DRE due to it's location. [1] [4] [5]

Pain during vaginal examination (VE) [3]

If the cause for peritonitis is endometritis, salpingo-oophoritis, tubo-ovarian abscess there will be pain in VE [3]

Differential Diagnoses

Fact

Explanation

Abdominal aneurysm [1]

A ruptured abdominal aneurysm causes blood to leak into the peritoneal cavity and might give rise to hemoperitoneum and resultant peritonitis. A typical patient is an elderly male presenting with acute abdomen with hypotension, shock [1] [2]

Acute Appendicitis [3] [4]

Typical presentation is initial peri-umbilical pain which later migrates to the right iliac fossa (RIF). Other symptoms are fever, nausea, vomiting. Ruptured inflamed appendix can cause peritonitis as well. [3] [4]

Mesenteric Ischemia [5]

When the blood supply is inadequate to the intestines via mesenteric vessels, results in bowel ischemia and eventual gangrene of the bowel wall and presents as acute abdomen. [5]

Pyelonephritis [6]

Infection of the kidney is called pyelonephritis and can present as acute abdomen. Also infection of the kidney, it self can cause peritonitis. [6]

Whipple Disease [7]

This is a rare multisystem disorder characterized in which patient has malabsorption, mesenteric lymph node enlargement, arthritis, and skin pigmentation and considered as a differential diagnosis. [7]

Familial Mediterranean fever [8]

Recurrent episodes of fever, peritonitis, pleuritis, synovitis are observed and mainly affects Jews and Arabs. Abdominal pain that may progress to peritonitis is seen and resembles a surgical abdomen. [8]

Granulomatous peritonitis [9]

This occurs in parasitic infestations, sarcoidosis, tumors, Crohn's disease, And symptoms due to peritoneal irritation could occur. [9]

Gynecologic disorders [10]

Pelvic inflammatory disease, Rupture of a ovarian cyst, ectopic pregnancy can give rise to acute abdomen. These may be the cause for peritonitis as well [10]

Perforated viscus [3]

Gastrointestinal perforation is one of the most common cause of peritonitis. Release of blood, bile acid, gastirc acid, feces can inflame peritoneum and cause secondary peritonitis. [3]

Investigations - for Diagnosis

Mostly a high white blood cell count is obeserved. But severe sepsis may even cause a leukopenia. Hypersplenism in spontaneous bacterial peritonitis, may reduce the white cell count. [1] [5] [6]

Liver function tests [5]

Spontaneous bacterial peritonitis (SBP) may occur in the presence of liver cirrhosis, therefore to assess liver function, this is done. [5]

Amylase and lipase [5]

may be done if pancreatitis is suspected as a differential diagnosis for acute abdomen. [5]

Blood culture [5]

When a patient is in sepsis, this can be postive and may help guide antibiotic therapy as well. [5]

serum albumin [2] [4] [5]

This measurement of the serum-to-ascites albumin gradient (SAAG) more than 1.1 is noted in SBP. [2] [4] [5]

Arterial blood gas analysis [5]

Patient may be in an acidotic state due to intravascular hypovolaemia and hypoxemia. [5]

Urineanalysis [5]

To rule out pyelonephritis. [5]

Peritoneal fluid analysis [2] [4] [5]

An ascitic fluid neutrophil count of greater than 500 cells/µL points towards the diagnosis of spontaneous bacterial peritonitis and the fluid should be evaluated for glucose, lactate dehydrogenase (LDH), protein, cell count, Gram stain, and aerobic and anaerobic cultures and also for AFB as well. Amylase analysis is helpful if pancreatitis is suspected [2] [4] [5]

Bedside reagent strips [2] [5]

A portable spectrophotometric device is used to for diagnosis [2] [5]

Abdominal x-ray [1] [3] [5]

Perforated viscus may show air under the diaphragm. [1] [3] [5]

Abdominal ultrasound [1] [3] [5]

Intra-abdominal abscesses, ascitis, can be assessed [1] [3] [5]

CT-abdomen [1] [3]

This also shows ascitis with a high sensitivity and can also detect abscesses [1] [3]

MRI- abdomen [5]

Intra-abdominal abscesses are diagnosed with a high sensitivity due to increased soft tissue resolution. [5]

Contrast studies [5]

Upper GI follow through with gastrograffin, colorectal enema with contrast, fistulogram are done when peritoneal abscess are suspected. [5]

Peritoneal biopsy [2]

To diagnose tuberculous peritonitis, or any malignancies which cause ascitis. [2]

Investigations - Fitness for Management

Fact

Explanation

Coagulation profile [1]

In spontaneous bacterial peritonitis (SBP), associated with liver cirrhosis, a diagnostic paracentesis is done to diagnose SBP. Prior to that a coagulation profile is needed to exclude any bleeding tendency. [1]

Management - General Measures

As there's hypovolemia, fluid replacement is done and regular monitoring of vital parameters such as blood pressure, pulse, urine output are done and blood gas analysis, hemoglobin and hematocrit, serum electrolytes and renal function tests are done to detect any complications. [1]

Nutrition [1] [2] [3]

Enteral nutrition is considered better thatn parenteral nutrition as it has a low complications rate . However parenteral nutrition is used if there are any contraindications for enteral nutrition. Sepsis leads to increased catabolism therefore high calorie diet may be required [1] [2] [3]

Patient education [1]

Patient should be education the aetiology of the disease, nature and course, importance of treatment and the options available for treatment. [1]

Management - Specific Treatments

Fact

Explanation

Antibiotic therapy [1] [2] [6]

Many antibiotic regimes are available for the treatment of intra-abdominal infections mainly with broad spectrum antibiotics. Gram-positive, gram-negative bacteria and anaerobic coverage is essential. Agents which are commonly used are cefotaxime, aminoglycoside, ampicillin, and sulfamethoxazole.Carbapenems such as Meropenem, Fluroquinolones are also used. [1] [2] [6]

No operative drainage (Percutaneous drainage) [2]

Percutaneous drainage under ultrasound or CT guidance for abscesses is carried out. [2]

Surgical drainage [2] [3]

Open drainage or laparoscopic drainage is carried out in deep seated abscesses. [2] [3]

Therapeutic paracentesis [4]

Sometimes in patients with ascitis, serial paracentesis are needed when fluid is keep on accumulating. This is done as a supportive management.[4]

Antibiotic prophylaxis [1] [6]

Prophylaxis is indicated for patients with a history of SBP, Presenting with an upper GI hemorrhage, Low total protein level in ascitic fluid and antibiotics used are Norfloxacin , Ciprofloxacin, trimethoprim-sulfamethoxazole [6]